Follow-up to r1620274: stop reinventing the wheel.

* subversion/tests/cmdline/relocate_tests.py
  (relocate_and_propset, single_file_relocate): Use the existing action
   tool to create the initial (untracked) greek repository instead of
   copying (part of) the implementation.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1620311 13f79535-47bb-0310-9956-ffa450edef68